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OSSA 10
May 22nd, 9:00 AM - May 25th, 5:00 PM
Trust based on bias: Cognitive constraints on
source-related fallacies
Steve Oswald
University of Neuchâtel, Cognitive Science Centre
Christopher Hart
Northumbria University, Department of Humanities
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Trust based on bias: Cognitive constraints on source-related
fallacies
STEVE OSWALD
Cognitive Science Centre
University of Neuchâtel
Espace Louis-Agassiz 1, CH-2000 Neuchâtel
Switzerland
steve.oswald@unine.ch
CHRISTOPHER HART
Department of Humanities
Northumbria University
Lipman Building, Newcastle upon Tyne, NE1 8ST
United Kingdom
christopher.hart@northumbria.ac.uk
ABSTRACT: This paper advances a cognitive account of the rhetorical effectiveness of fallacious
arguments and takes the example of source-related fallacies. Drawing on cognitive psychology and
evolutionary linguistics, we claim that a fallacy enforces accessibility and epistemic cognitive
constraints on argument processing targeted at preventing the addressee from spotting its
fallaciousness, by managing to prevent or circumvent critical reactions. We address the evolutionary
bases of biases and the way that these are exploited in fallacious argumentation.
KEYWORDS: ad hominem, ad populum, ad verecundiam, cognitive biases, cognitive pragmatics,
epistemic vigilance, fallacies, information processing, relevance
1. INTRODUCTION
Much of the research concerned with fallacies has been typological in nature,
attempting to delineate particular kinds of fallacies. Among the fallacies identified
are those which relate to the reliability of third party sources, either by making
appeal to those sources (ad populum and ad verecundiam) or attempting to discredit
them (ad hominem). This research has been focused on specifying the characteristics
of these arguments, including, for example, what it is that makes them fallacious
(Walton, 2006; van Eemeren & Grootendorst, 2004). This paper will approach these
fallacies – referred to hereafter as source-related fallacies – within an explanatory
framework in which rhetorical effectiveness is seen as a product of cognitive
constraints and biases (see Hart, 2011, in press.; Oswald, 2011, forth.). We will
therefore not be concerned with descriptive and definitional issues. Rather, we aim
to illuminate how and why illegitimate invocations of third parties may succeed in
convincing the audience of a given conclusion.
Mohammed, D., & Lewiński, M. (Eds.). Virtues of Argumentation. Proceedings of the 10th International Conference of the Ontario
Society for the Study of Argumentation (OSSA), 22-26 May 2013. Windsor, ON: OSSA, pp. 1-13.
STEVE OSWALD AND CHRISTOPHER HART
This framework draws on insights from cognitive science, in particular
cognitive pragmatics (Sperber & Wilson, 1995; Wilson & Sperber, 2012) and
evolutionary approaches to communication (Sperber et al., 2010). We will argue
that there are cognitive principles pertaining to the use and processing of sourcerelated fallacies which account for their rhetorical effect. These principles take the
form of cognitive heuristics (see Gigerenzer, 2008) which guide inferential
processes at the level of evaluation.1 Specifically, we are suggesting that sourcerelated fallacies exploit our processing mechanisms, which are usually reliable and
accurate, but which are by their necessarily fast and frugal nature inherently fallible.
In section 2 we introduce the three fallacies we are concerned with. Section 3
presents an evolutionary approach to argumentation which suggests that ad
populum and ad verecundiam arguments meet the demands of hearers’ systems for
epistemic vigilance (Sperber et al., 2010) by presenting sources mistakenly deemed
reliable whilst ad hominem alerts epistemic vigilance to characteristics of the
targeted source which misguidedly betray their unreliability. In section 4 we
elaborate an account of fallacy processing in terms of cognitive constraints and
biases. Here, we focus on the information-selection mechanisms at play in argument
processing. We suggest that these fallacies work, as a consequence of evolved
cognitive biases (see e.g. Pohl, 2004) and relevance considerations in processing, by
constraining the information sets available to the hearer, resulting in a hindrance to
critical evaluation. Section 5 illustrates our claims with an analysis of each argument
as found in political discourse.
2. SOURCE-RELATED FALLACIES
Source-related fallacies may be identified as those whose premises predicate
something about the sources of information used in the course of the argument.
These can be divided into arguments which, in order to support the speaker’s
conclusion, resort to sources of information in the form of authorities and majorities
(ad verecundiam and ad populum respectively) and those which attack them (ad
hominem). Following Walton (2006), the fallaciousness of these arguments can be
captured in their failure to satisfactorily answer critical questions associated with
underlying argument schemes.
Ad verecundiam, for example, can be broadly construed as a problematic
appeal to expert opinion. Of course, not all appeals to expert opinion are fallacious.
What determines the fallaciousness of an appeal to expert opinion, according to
Walton, is whether it satisfactorily answers a set of critical questions associated
with an underlying argumentation scheme. The argumentation scheme behind
appeals to expert opinion can be presented as below (Walton, 2006, p. 87):
Argumentation scheme for appeal to expert opinion
Major premise: Source E is an expert in subject domain D containing Proposition A.
Minor premise: E asserts that proposition A (in domain D) is true (false).
Conclusion: A may plausibly be taken to be true (false).”
1
See Oswald (2011, forth.) on constraints operating at the level of comprehension.
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STEVE OSWALD AND CHRISTOPHER HART
The critical questions that determine whether or not a particular
instantiation of the scheme is fallacious are formulated as follows (Walton, 2006, p.
88):
Expertise Question. How credible is E as an expert source?
Field Question. Is E an expert in the field that A is in?
Opinion Question. What did E assert that implies A?
Trustworthiness Question. Is E personally reliable as a source?
Consistency Question. Is A consistent with what other experts assert?
Backup Evidence Question. Is E’s assertion based on evidence?
Ad verecundiam is the fallacious variant of the argument scheme which arises
when any one of these questions receives a negative answer. Walton formulates
similar schemes and associated critical questions to assess the fallaciousness of
appeals to popular opinion and attacks of the source of a given proposition. For
reasons of space, we do not present these here but refer the reader directly to
Walton (2006). However, we note that ad populum and ad hominem, like ad
verecundiam, are the fallacious variants of respective underlying argument schemes.
One critical question which crops up in all three argument schemes concerns
the reliability and/or credibility of the source of information that is invoked. In all
three, what is at stake is not the content of the argument but, rather, something
external to it. In the case of ad verecundiam, the strength of the argument lays in the
perceived trustworthiness of the source. The strength of ad populum arguments lays
not in the faith one has in a particular source but in the weight carried by
widespread belief. Ad hominem similarly operates on the parameter of authority but
in the reverse direction where it dismisses a given proposition on the grounds that it
is asserted by a source whose legitimacy is cast into doubt.
In the next section, we will argue that the critical abilities underlying
Walton’s critical questions are encapsulated in the evolved, cognitive competences
of communicators. These competences may take the form of what Sperber et al.
(2010) refer to as epistemic vigilance. Source-related fallacies, we will suggest, work
by manipulating epistemic vigilance where they can be characterised as “failed
diagnostic strategies” (Jackson, 1996, p. 111) reinterpreted in cognitive and
adaptationist terms.
3. EPISTEMIC VIGILANCE
On an evolutionary account of communication, language must have evolved initially
for purposes of cooperation (Sperber, 2001; Hurford, 2007). However, any such
system of cooperation is susceptible to exploitation in the form of deception (Origgi
& Sperber, 2000). For communication to stabilise within the species, therefore, “all
cost-effective available modes of defence are likely to have evolved” (Sperber, 2000,
p. 135). For Sperber et al. (2010, p. 359) these defences amount to “a suite of
cognitive mechanisms for epistemic vigilance”. Epistemic vigilance, according to
Sperber et al., is both content-directed and source-directed. In content-directed
vigilance, hearers attend to the logical consistency of the message as well as its
plausibility given background assumptions. In source-directed vigilance, hearers
3
STEVE OSWALD AND CHRISTOPHER HART
assess the trustworthiness of speakers, defined as judgements of competence,
benevolence, expertise, reliability, credibility, etc.
In the practice of argumentation – a communicative practice by which
speakers provide information in support of claims in order to convince others –
hearers exercise epistemic vigilance in order to avoid being misled. The functioning
mechanism here is an argumentative module which operates both in the production
and evaluation of arguments. In the evaluation of arguments, the mechanism is
responsible for identifying reasons to (dis)believe the conclusion of an argument
(Mercier & Sperber, 2009, 2011). The module, here, takes as input claims and
combines them with contextual information to yield an intuitive representation
concerning the relationship between the premises and the conclusion contained
within the argument. This then allows the hearer to make a judgement on the
argument’s acceptability. In the production of arguments, the argumentative module
allows speakers to formulate arguments in ways which are intended to satisfy or
otherwise exploit the hearer’s epistemic vigilance.
In so far as we are interested in the rhetorical effectiveness of fallacies, we
are interested here in the evaluative dimension of the argumentative module.
Moreover, because we are concerned with source-related fallacies in particular, we
will deal only with source-directed vigilance.
Epistemic vigilance amounts to a diagnostic strategy selected for in the
evolution of communication. However, by virtue of the resource-bound nature of
our cognitive architecture, it remains fallible (see section 4). It is precisely this
imperfection, we suggest, that fallacies exploit. Ad verecundiam and ad populum
appear to provide sufficient evidence to satisfy epistemic vigilance by presenting the
conclusion as entertained by external sources the hearer is expected to trust. In ad
verecundiam, it is the expertise, authority, competence, credibility and benevolence
etc. of the source that lends epistemic strength to the conclusion. In ad populum, the
epistemic strength lays, in part, in the sense of likelihood derived from learning that
a large number of people take the conclusion to be true. Ad hominem, by contrast,
directs hearers to the epistemic weakness of the conclusion advanced by the
targeted source by making explicit their untrustworthiness. Ad hominem itself
therefore satisfies epistemic vigilance directed at the speaker (the utterer of the ad
hominem) but alerts epistemic vigilance directed toward the targeted source.
The three fallacies, then, may overcome epistemic vigilance by providing
apparently satisfactory evidence; the first two rely on perceived trustworthiness
whilst the latter directs epistemic vigilance towards ‘mistakenly’ assessing the
unreliability of the source as a sufficient reason to reject the conclusion they
advance. When the fallacies are successful, then, it means that the cognitive system
has not found it relevant to question the evidence provided within the argument. In
other words, the system has failed to mobilise additional (critical) information
which should alert the hearer to the argument’s fallaciousness. To account for why
hearers fail to recognise these arguments as fallacious, we turn to particular
cognitive constraints and biases involved in argument processing.
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STEVE OSWALD AND CHRISTOPHER HART
4. PROCESSING CONSTRAINTS AND BIASES
One major constraint on argument processing consists in information selection
(Oswald, 2011, forth.; Maillat & Oswald, 2009, 2011). In this section we suggest that
information selection may be influenced by evolved cognitive biases and
considerations of relevance such that the importance of critical questioning is
downplayed. As a general theory of human cognition, applied to communication,
and to the extent that it formulates precise criteria of information selection,
Relevance Theory (henceforth RT) allows a handle on argumentative phenomena of
the kind we are concerned with here.
4.1 Relevance Theory
RT is a model of ostensive-inferential communication which postulates that the
cognitive mechanisms involved in comprehension are regulated according to
relevance, defined as an optimal balance between cognitive costs and benefits.
Understanding a speaker’s utterance amounts to identifying the interpretation that
best satisfies the ratio between the cognitive efforts incurred in processing the
utterance (including the selection of contextual information required to make sense
of it) and the cognitive effects that can be anticipated. Cognitive effects are defined
in terms of an assumption’s usefulness to the cognitive system (i.e., its ability to
provide reliable new information and to revise, discard or strengthen previously
held information). In interpretation, hearers follow a path of least effort in
calculating cognitive effects and cease further processing as soon as expectations of
relevance are met.
This technical definition of relevance highlights two crucial parameters
according to which information is selected. These are captured by the extent
conditions of relevance (Sperber & Wilson, 1995, p. 125):
Extent condition 1: an assumption is relevant in a context to the extent that its
contextual effects in this context are large.
Extent condition 2: an assumption is relevant in a context to the extent that the
effort required to process it in this context is small.
Relevance, thus, is a function of accessibility, since that which is accessible is
less effortful to process. At the same time, it is a function of epistemic strength,
where adding, revising or discarding assumptions is, of course, an epistemic matter.
Two important points emerge for our purposes: (i) relevance assessments are
heuristic in nature and therefore susceptible to error; (ii) the extent conditions of
relevance may extend beyond the comprehension procedure to provide parameters
for information selection in argument evaluation.
In relation to the second point above, we suggest that fallacies work precisely
by prohibiting hearers from selecting critical information which would point to their
fallacious nature. This argument is founded on the principle that information
processing involves competition between information sets. As Sperber and Wilson
put it, “not all chunks of information are equally accessible at any given time” (1995,
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STEVE OSWALD AND CHRISTOPHER HART
p. 138). Certain information is selected, according to its relevance in a particular
context, at the expense of other information which, by the procedure, is inverseproportionately less relevant and therefore not attended to. In what follows, we
argue that this selection effect is, at least in part, a function of evolved cognitive
biases.
4.2 Cognitive biases
Cognitive biases are errors in judgement, thinking and memory which can be
predicted to arise from heuristics in information processing (Tversky & Kahneman,
1974; Pohl, 2004; Gigerenzer, 2008). Heuristics are decision-making strategies
which are generally useful and have evolved to cope with uncertainty, resource
limitations and time pressures, etc. However, by their ‘fast and frugal’ nature, they
can sometimes lead to “severe and systematic errors” (Tversky & Kahneman, 1974,
p. 1124).
Certain cognitive biases bring about errors specifically in epistemic
judgements. For example, a conformity bias can be shown to result in something like
a ‘group effect’ (Henrich & Boyd, 1998). Such heuristics and biases may be rooted in
the evolution of social cooperation. For example, as Sperber et al. (2010, p. 380)
state:
If an idea is generally accepted by the people you interact with, isn’t this a good
reason to accept it too? It may be a modest and prudent policy to go along with the
people one interacts with, and to accept the ideas they accept. Anything else may
compromise one’s cultural competence and social acceptability.
The claim we are making in this paper is that cognitive biases of this kind, in
conjunction with relevance considerations in information processing, may explain
the effectiveness of certain fallacies, including source-related fallacies.
Cognitive biases are triggered by fallacies and in turn provide additional
input to the argumentative module. Given what is at stake, biases have evolved to
make this input highly relevant to the argumentative module. As a result, in
evaluating the argument the argumentative module may deem it unnecessary to
engage in further cognitive processing, including asking critical questions. The
argument satisfies expectations of relevance and, by consequence, epistemic
vigilance too; it therefore goes through the system unchallenged.
On this account, fallacies are directly related to cognitive biases which make
some information relevant and other, critical information irrelevant. Ad populum
operates on the back of a conformity bias.2 We can make a similar case for ad
verecundiam. For example, the famous Milgram experiments (1974) observed an
‘obedience effect’ which is presumably, at least partly, the product of an authority
bias. Ad verecundiam is able to activate precisely this bias. It usually pays to go along
with majorities because to do so is efficient and because not to do so compromises
Maillat (in press) has suggested that ad populum also hinges on the bias behind the validity effect
(Hackett Renner, 2004) where repetition can be seen to contribute to acceptance of information.
2
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STEVE OSWALD AND CHRISTOPHER HART
one’s social inclusion. It may pay to go along with authorities for similar reasons.
Moreover, experts possess information in particular domains which hearers might
not otherwise have access to and which, by virtue of their expertise, is usually
reliable. It is therefore perfectly rational to take the word of an expert. Fallacies, in
sum then, work in convincing audiences because they exploit the inherent fallibility
of heuristics which are, in the normal course of events, helpful.
Biases related to conformity and expertise make what majorities and
authorities say or think epistemically strong to the degree that hearers are less
likely to subject the argument to full critical evaluation. Ad hominem can be analysed
as operating on the same mechanisms, though it may be considered the flipside of
ad verecundiam. Whilst ad verecundiam tries to establish the source’s
trustworthiness, ad hominem tries to undermine their trustworthiness. And since
the risks of communication are so great, any suggestion that the source is not
credible is relevant enough for the system that the hearer does not properly
consider the content of the argument or critically question the significance of the
source’s credibility in relation to the quality of the argument.
In the final section, we see how all of this plays out in particular illustrative
analyses.
5. ILLUSTRATION AND ANALYSIS
5.1 Ad verecundiam3
In 2004, prior to a national vote about the possibility for 2nd and 3rd generation
immigrants to benefit from simplified naturalisation procedures, the Swiss far‐right
political party UDC4 published a campaign ad in several newspapers entitled
“Thanks to automatic naturalisation, the Muslims soon to be in majority?” (“Grâce
aux naturalisations automatiques, les Musulmans bientôt en majorité?”).5 The
document contains three graphs with statistics and a text explaining to the reader
that simplifying these naturalisation procedures will result in a dramatic increase of
Muslims in the country, which is something they implicitly present as an
undesirable threat to the Swiss identity. In explicit terms, they merely refer to this
as “a problem”. Interestingly, the text mentions the testimony of an expert, Sami
Aldeeb, who works for the Swiss Institute of Comparative Law at the University of
Lausanne. Here is the text:
(1)
“Sami Aldeeb, who is responsible for Arabic and Muslim law at the
Swiss Institute of Comparative Law in Lausanne, has an even more
drastic vision of the situation: ‘The proportion of Muslims in
The example discussed in this subsection is taken from Burger et al. (2006), who perform a Speech
act-theoretic analysis of the corpus. We reinterpret here some of their findings within our
framework. This article also contains a reproduction of the campaign ad.
3
4
UDC stands for “Union Démocratique du Centre”, i.e. ‘Democratic Union of the Centre’.
The ad can be seen in the appendix of the online version of Burger et al. (2006) at the following
address: http://mots.revues.org/609 (last accessed, 25.06.2013)
5
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STEVE OSWALD AND CHRISTOPHER HART
Switzerland triples every ten years. Today, 310’000 Muslims legally
reside in the country and some 150’000 others illegally reside in
Switzerland. In twenty years, they will be in majority. There will be
more Muslims than Christians in Switzerland by then’. And that is
where the problem lies, because ‘Muslims place their religion above
our laws.’”6
The argument contained in this excerpt is quite complex but minimally offers
the premise in (2) as a main reason to defend the conclusion in (3):
(2)
(3)
Explicit premise: Muslims place their religion above our laws.
Conclusion: It is a problem that in twenty years Muslims will
outnumber Christians in Switzerland.
The argument contained in (1) is part of a more global pragmatic
argumentation developed throughout the text which enjoins readers to vote against
facilitated naturalisations in order to avoid the undesirability (in the opinion of the
authors) of a majority of Muslims. We are specifically interested here in (i) the
perceived authoritative character of the expert that is called in and (ii) the way the
argument links the premises to its conclusion.
Sami Aldeeb is presented as an expert in comparative law, which indeed he
was at that time. His testimony on Muslim law should thus at first sight be
(reasonably) perceived as relevant and trustworthy. As a consequence, the contents
expressed between quotation marks are likely to be perceived as epistemically
strong. What the reader doesn’t know is that his words are actually quoted from a
prior interview he gave to the Swiss tabloid Blick, the publication of which Aldeeb
had not approved himself, because instead of reflecting his actual point, which
consisted in the defence of an integrationist model, his words were used for their
potential islamophobic connotations (Burger et al., 2006, p. 17). We note that unless
the reader personally knows Aldeeb, they have no way of knowing this and they
therefore have no cause to address the critical questions associated with the
relevant argument scheme. In other words, epistemic vigilance is satisfied. This is
problematic, however, because the reader has been prevented from critically
assessing the expert’s testimony on the issue.
A second problem with the use of the expert source in this argument, as
noted by Burger et al. (ibid.), lays in the tentative inferences the reader is likely to
draw from the Arabic resonance of the name Sami Aldeeb. In the absence of further
evidence, the reader might infer from his name that the expert is himself Muslim,
which would therefore tend to represent him as someone who does not hold hostile
Original text: “Sami Aldeeb, responsable du droit arabe et musulman à l’Institut suisse de droit
comparé à Lausanne, a une vision encore plus drastique de la situation: ‘La proportion de Musulmans en
Suisse triple tous les dix ans. Aujourd’hui, 310'000 Musulmans vivent légalement et quelque 150'000
autres vivent illégalement en Suisse. Dans vingt ans, ils seront la majorité. Il y aura alors plus de
Musulmans que de Chrétiens en Suisse’. Et c’est bien là que réside le problème, car ‘Les Musulmans
placent leur religion au-dessus de nos lois.’”
6
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STEVE OSWALD AND CHRISTOPHER HART
preconceptions about Muslims, i.e., as a speaker who is unbiased towards Muslims.
Under this interpretation, his words, which negatively represent Muslims, cannot be
taken to be motivated by an inherent dislike for Muslims. This, in turn, positively
affects the objective quality of the expert and increases his perceived
trustworthiness. Nowhere in the document is the reader discouraged from drawing
this inference, which is actually false; Sami Aldeeb is in fact a Christian Palestinian.
Again, this piece of information would be highly relevant for the reader to establish
source credibility. Its absence only increases the chances of the false inference being
drawn and as a consequence boosts the epistemic status of whatever the ‘unbiased’
expert has to say.
A third problem with this argument can be identified in the problematic
endorsement of the argumentative link presented in (1). A close look at the text
shows that Sami Aldeeb only provides contents which are then used in the premises
of the argument (the propositions given in quotation marks). The semantic content
of the conclusion, but also the argumentative connective ‘because’, are however
outside quotation marks. We hypothesise that inattentive readers might overlook
this and take Aldeeb to be responsible for the argument being made for the
following three reasons. Firstly, his testimony is framed as a “drastic vision of the
situation”. Drastic and dramatic visions of a situation are likely to foreground
problematic issues. Secondly, the negative connotations of the statements he is
responsible for appear in bold characters, making them more salient than both the
conclusion and the connective. Thirdly, assuming the reader’s epistemic vigilance
filters are satisfied of Aldeeb’s trustworthiness in the way described above, the
credibility of his words and their islamophobic connotations is compatible with the
interpretation that they constitute a serious problem.
(1) is a particularly interesting illustration of the ad verecundiam fallacy. The
features of the text highlight the trustworthiness of the source in a way that should
meet the demands of epistemic vigilance.
5.2 Ad populum
In 2005, Michael Howard, former leader of the British Conservative Party, delivered
a speech on immigration in Telford in which he argued for a restrictive policy on
immigration and specifically on the asylum system. The main standpoint of his
discourse is found in the following excerpt:7
(4)
“It’s not racist to talk about immigration. It’s not racist to criticise the
system. It’s not racist to want to limit the numbers”
In order to support these claims, he verbalises the voice of the majority in the
following ways:
7
The complete transcript can be found here (last accessed 08.03.2013):
http://news.bbc.co.uk/2/hi/uk_news/politics/vote_2005/frontpage/4430453.stm
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STEVE OSWALD AND CHRISTOPHER HART
(5)
(6)
(7)
(8)
“The majority of British people (...) are united on this issue.”
“Everyone wants new people to settle as long as numbers are limited.”
“Talk to people and whatever their background, religion or the colour
of their skin – they ask the same thing: ‘Why can't we get a grip on
immigration?’ These are the people who are always ready to welcome
genuine refugees to Britain, or families who want to work hard and
make a positive contribution to our country.”
“But I’ve lost count of the times that British people of ethnic
backgrounds have told me that firm but fair immigration controls are
essential for good relations.”
The implicit overall argumentation produced by Howard in this speech is an
appeal to popular opinion which can be minimally reconstructed in the following
way:
(9)
Everyone, like us, says there is a problem with immigration: this
cannot be racism, since it is unlikely that all of the people denoted by
‘everyone’ are wrong and racist.
We take this argumentation to be an instance of the ad populum fallacy for
two reasons. First, it fails to satisfactorily answer the critical questions associated
with the scheme for arguments from popular opinion (in particular, we do not have
conclusive evidence that the large majority invoked by Howard actually endorses
what he says). Second, the way popular opinion is portrayed by Howard
systematically and repeatedly presents “everyone” as morally respectable. However,
the grounds for this appraisal are ill-evidenced. Nevertheless, the moral qualities of
the majority referred to confer epistemic strength on the arguments in the following
ways.
The third party invoked in support of Howard’s conclusions is a majority
depicted as: (i) morally virtuous, i.e., hard-working and welcoming (7); and (ii) nonracist and unbiased towards foreigners, because they are themselves of different
ethnic backgrounds and origins (7, 8). We have seen previously (see section 4) that
the voice of majorities carries epistemic weight, to the extent that it is perfectly
rational to consider that a large amount of people united on a given issue are
unlikely to be wrong. Depicting a majority as morally virtuous further adds to the
perceived trustworthiness of the source. This in turn ensures that the assumptions
reported to be endorsed by the majority are highly salient in the hearer’s cognitive
environment as he processes Howard’s speech.8
The cognitive bias responsible for the validity effect (see Hackett Renner,
2004, Maillat, in press.) can here be seen to operate too: Howard repeats on several
occasions in this discourse the idea that the majority of British people agree with
him, and this could also be seen as a way of increasing the epistemic value of the
majority’s opinion on the subject. Additionally, since repetition makes for salience
The cognitive environment is defined as the set of assumptions that are manifest to an individual at
any given time (Sperber & Wilson, 1995).
8
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STEVE OSWALD AND CHRISTOPHER HART
and accessibility, the fact that Howard’s (and the majority’s) opinion is repeated
across the speech makes it more accessible than alternative information sets. From
the perspective of cognitive processing, this means that it stands a better chance of
being represented than alternative, less salient, information sets, which could
contain critical information pertaining to the argument.
Finally, as mentioned above in section 4.2, the conformity bias is exploited in
Howard’s words in his positive characterisation of the majority whose opinion he
reports. The social consequences of disagreeing with a morally good, unbiased and
non-racist majority are potentially disastrous for an individual. In the Telford
speech, Howard’s depiction of the majority he summons in support of his claim
could very well be seen as a way of constraining any potential critical reaction on
behalf of the audience.
5.3 Ad hominem
During Prime Minister’s Questions on October 18 2011, Russell Brown, Labour MP,
asked David Cameron, Britain’s current Prime Minister, if he could provide a list of
people affected by the Adam Werritty scandal.9 To this, Cameron replied with the
following:10
(10)
“It comes slightly ill from a party to lecture us on lobbying when we
now know the former defence secretary is working for a helicopter
company, the former home secretary is working for a security firm,
Lord Mandelson, well he’s at Lazards, and even the former leader, the
former prime minister, in the last few months he’s got £120,000 for
speeches to Credit Suisse, Visa and Citibank. He told us he’d put the
money into the banks, we didn’t know he’d get it out so quickly.”
Russell’s question required the PM to provide information about some
lobbying practices his party had been accused of. Instead, the PM evades the attack
by highlighting the opposition’s own dubious practices, and therefore their nonlegitimacy in filing attacks on the issue. Cameron, then, has used the tu quoque
variant of the ad hominem fallacy. This argument is fallacious because “the hypocrisy
of the arguer is not necessarily evidence of the falsity of what she argues” (see Aikin
2008, p. 156).
By pointing to the hypocrisy of his attacker, Cameron is attempting to
undermine their credibility. This is quite common in political discourse (and
Adam Werritty is a business investor who was a close friend to Liam Fox, the then Secretary of State
for Defence. Werritty allegedly accompanied Fox on overseas engagements acting as an informal
adviser. Werritty was able to use his position to provide access to the minister. This conflict of
interest prompted a series of investigations which eventually lead to Fox’s resignation in October
2011.
9
10
See the transcript of the argument here (last accessed 08.03.2013):
http://www.heraldscotland.com/politics/political-news/cameron-attacks-brown-onspeeches.15458313
11
STEVE OSWALD AND CHRISTOPHER HART
political debates in particular). However, (10) is remarkable for a specific reason.
Not only does Cameron provide evidence of dubious practices of the opposition, he
provides a significantly higher number of such practices in order to outweigh
Russell’s attack. In the situation where epistemic vigilance is required to assess the
trustworthiness of third parties which are being charged with inconsistency or
hypocrisy, one could reasonably assume that the most trusted source would be the
one to suffer the least damage. By identifying numerous members of the opposition
and the dubious practices they are accused of, Cameron overwhelmingly outcharges
his opponent. (10) further sets the stage for a generalising inference to be drawn
where hearers might extend the negative traits of some members of the opposition
to the whole party.
Cognitively speaking, then, (10) foregrounds information meant to destroy
the opponent’s legitimacy. The tu quoque attack is particularly strong here from an
epistemic perspective because it presents different instances of the same
wrongdoing, whilst the original attack it addresses only questions the extent to
which the Werritty scandal has damaged the ruling party. For reasons of relevance
related to the possibility and usefulness of identifying concrete instances of the
problem, this may prevent the audience from mobilising critical information. They
might, accordingly, be left with no grounds to critically question the argument
produced by Cameron. This, in turn, would result in the argument not being
challenged and is precisely what makes the fallacy effective.
6. CONCLUSION
According to Hamblin, the standard treatment of fallacies is to suggest that a
“fallacious argument … is one that seems to be valid but is not so (Hamblin, 1970,
p.12, original emphasis). This, he argues, does not allow for the elaboration of a
consistent theory of fallacies. However, we take his statement to highlight a crucial
feature of fallacies which precisely explains their effectiveness: hearers fall for
fallacies because they do not spot them. This can be accounted for by examining the
evolved, cognitive constraints involved in information processing.
The heuristics and biases programme and RT together provide an
explanatory framework for interpreting the rhetorical effectiveness of fallacies
which we characterise in terms of the consequences they have for epistemic
vigilance. We have considered the case of source-related fallacies and argued that
these implement constraints on the information sets that will eventually be deemed
relevant as hearers process the argument. These constraints explain that critical
questions, which we see as embodied in epistemic vigilance, are neither asked nor
answered.
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